public interface DistributedLockRepository extends ReactiveCrudRepository<DistributedLock, String> { @Query("SELECT * FROM distributed_lock WHERE lock_key = :#{[0]} for update ") Mono<DistributedLock> findByLockKey(String lockKey); } 

 @Override public boolean acquireLock(DistributedLockDO distributedLockDO) { try { return Boolean.TRUE.equals(distributedLockRepository.findByLockKey(distributedLockDO.getLockKey()) .publishOn(Schedulers.boundedElastic()).map(distributedLock -> { if (distributedLock != null && StringUtils.isNotBlank(distributedLock.getLockValue()) && !StringUtils.equals(distributedLock.getLockValue(), distributedLockDO.getLockValue()) && System.currentTimeMillis() < distributedLock.getExpireTime()) { return false; } distributedLockDO.setExpireTime(distributedLockDO.getExpireTime() + System.currentTimeMillis()); if (distributedLock != null) { if (!StringUtils.equals(distributedLock.getLockValue(), distributedLockDO.getLockValue())) { distributedLock.setLockValue(distributedLockDO.getLockValue()); } distributedLock.setNewLock(false); return distributedLockRepository.save(distributedLock).block() != null; } distributedLock = new DistributedLock(); distributedLockDOToEntity.copy(distributedLockDO, distributedLock, null); return distributedLockRepository.save(distributedLock).block() != null; }).as(operator::transactional).block()); } catch (R2dbcDataIntegrityViolationException e) { // being scrambled by other threads to succeed return false; } } 

Caused by: io.r2dbc.spi.R2dbcTimeoutException: Lock wait timeout exceeded; try restarting transaction	at dev.miku.r2dbc.mysql.ExceptionFactory.createException(ExceptionFactory.java:69)	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: Error has been observed at the following site(s):	*__checkpoint ⇢ SQL "UPDATE distributed_lock SET lock_value = ?, expire = ? WHERE distributed_lock.lock_key = ?" [DatabaseClient] Original Stack Trace:	at dev.miku.r2dbc.mysql.ExceptionFactory.createException(ExceptionFactory.java:69)	at dev.miku.r2dbc.mysql.TextQueryHandler.accept(QueryFlow.java:317)	at dev.miku.r2dbc.mysql.TextQueryHandler.accept(QueryFlow.java:292)	at reactor.core.publisher.FluxHandleFuseable$HandleFuseableSubscriber.onNext(FluxHandleFuseable.java:176)	at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107)	at dev.miku.r2dbc.mysql.util.DiscardOnCancelSubscriber.onNext(DiscardOnCancelSubscriber.java:70)	at reactor.core.publisher.FluxPeekFuseable$PeekConditionalSubscriber.onNext(FluxPeekFuseable.java:854)	at reactor.core.publisher.MonoFlatMapMany$FlatMapManyInner.onNext(MonoFlatMapMany.java:250)	at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:200)	at reactor.core.publisher.FluxHandle$HandleSubscriber.onNext(FluxHandle.java:126)	at reactor.core.publisher.FluxPeekFuseable$PeekConditionalSubscriber.onNext(FluxPeekFuseable.java:854)	at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:491)	at reactor.core.publisher.EmitterProcessor.tryEmitNext(EmitterProcessor.java:299)	at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:27)	at reactor.core.publisher.EmitterProcessor.onNext(EmitterProcessor.java:265)	at dev.miku.r2dbc.mysql.client.ReactorNettyClient$ResponseSink.next(ReactorNettyClient.java:340)	at dev.miku.r2dbc.mysql.client.ReactorNettyClient.lambda$new$0(ReactorNettyClient.java:103)	at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:185)	at reactor.netty.channel.FluxReceive.drainReceiver(FluxReceive.java:279)	at reactor.netty.channel.FluxReceive.onInboundNext(FluxReceive.java:388)	at reactor.netty.channel.ChannelOperations.onInboundNext(ChannelOperations.java:404)	at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:93)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)	at dev.miku.r2dbc.mysql.client.MessageDuplexCodec.handleDecoded(MessageDuplexCodec.java:187)	at dev.miku.r2dbc.mysql.client.MessageDuplexCodec.channelRead(MessageDuplexCodec.java:95)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)	at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:327)	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:299)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)	at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1372)	at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1235)	at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1284)	at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:510)	at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:449)	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:279)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:995)	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)	at java.base/java.lang.Thread.run(Thread.java:829) <==